performance with LSI SAS 1064

[Scott Long]

Eric Anderson wrote:
> Lutieri G. wrote:
>> I've make a test with dd command:
>>
>> # time dd if=/dev/zero of=./8gbfile bs=1024k count=8192
>> 8192+0 records in
>> 8192+0 records out
>> 8589934592 bytes transferred in 155.653213 secs (55186362 bytes/sec)
>> 0.007u 25.129s 2:35.69 16.1%    55+6039k 117+68628io 0pf+0w
>>
>> in other terminal i ran iostat while dd were running and I get this:
>>
>> # iostat -I 1
>>       tty             da0            pass0             cpu
>>  tin tout  KB/t xfrs   MB   KB/t xfrs   MB  us ni sy in id
>>    1   61 25.23 52958 1305.07   0.00   0  0.00   0  0  8  0 91
>>    0  184 127.48 434 54.03   0.00   0  0.00   0  0  5  0 95
>>    0   61 127.49 440 54.78   0.00   0  0.00   0  0  5  0 95
>>    0   61 127.75 445 55.52   0.00   0  0.00   0  0  5  0 95
>>    0   61 127.49 442 55.03   0.00   0  0.00   0  0  4  0 96
>>    0   61 127.49 436 54.28   0.00   0  0.00   0  0  5  0 95
>>    0   61 125.27 425 51.99   0.00   0  0.00   0  0  5  1 94
>>    0   61 118.14 393 45.34   0.00   0  0.00   0  0  3  0 97
>>
>> average  54MB/s with or without hw.mpt.enable_sata_wc seted in 
>> loader.conf file.
>>
>> is it a normal speed for this adapter?!
>>
>>
> 
> 
> I'm confused - you said in your first post you were getting 3MB/s, where 
>  above you show something like 55MB/s.
> 
> You didn't say what kind of disks, or how many, the configuration, etc - 
> so it's hard to answer much.  The 55MB/s seems pretty decent for many 
> hard drives in a sequential use state (which is what dd tests really).
> 
> Your errors before were probably caused because your queue depth is set 
> to 255 (or 256?) and the adapter can't do that many.  You should use 
> camcontrol to reduce it, to maybe 32.  See the camcontrol man page for 
> the right usage.  It's something that needs setting on every boot, so a 
> startup file is a good place for it maybe.
> 
> Eric
> 
> 

Well, if he's using SATA (which I kinda assumed originally without
asking) then queue depth isn't going to matter; the MPT driver has no
interaction with how SATA NCQ operates, if he even has a rev of the
LSI chip that supports NCQ at all.  If he's using SAS, then queue
depth will only be a minor factor, CAM is pretty good at autosizing
the depth with minimal impact.  Now, if he's using SAS disks then
the boot tunable that I gave him will indeed have no impact at all.

I believe that the Sun 4100 uses 2.5" disks, whether SATA or SAS.
54MB/s is not all that bad for disks of this size.  It's pretty close
to what I would expect, actually.

Scott